2,6,6-Trimethyl-1-alkenoyl-cyclohexenones

ABSTRACT

Use of oxygenated alicyclic compounds, some of which are new, as perfuming and/or flavouring ingredients in the manufacture of perfumes and perfumed products and/or in the preparation of artificial flavours for foodstuffs, animal feeds, beverages, pharmaceutical preparations and tobacco products. Process for the preparation of said alicyclic compounds.

United States Patent Schulte-Elte et a1.

[ Dec. 16, 1975 2,6,6-TRIMETHYL-l-ALKENOYL- CYCLOHEXENONES Inventors: Karl-Heinrich Schulte-Elte; Henri Jindra, both of Geneva, Switzerland Assignee: Firmenich S.A., Geneva,

Switzerland Filed: Oct. 23, 1973 Appl. No.: 408,919

Foreign Application Priority Data Oct. 26, 1972 Switzerland 15691/72 Mar. 21, 1973 Switzerland 4096/73 11.8. C1 260/586 R; 131/17 R; 252/522;

260/348 C; 260/586 P; 426/171; 426/175 Int. C1. C07C 49/44 Field of Search 260/586 R References Cited UNITED STATES PATENTS 11/1968 Rowland et a1. 260/586 R 3,578,715 5/1971 Corbier et a1 260/586 R 3,803,217 4/1974 Schwieter et a1. 260/586 R 3,822,315 7/1974 Klein 260/586 R OTHER PUBLICATTONS Beilstein, Hand. Der. Org. Chem, V01. V11, III, Supp., IV, Teil, p. 3427, Formula I, (1969).

Primary ExaminerNorman Morgenstern Attorney, Agent, or Firm-Pennie & Edmonds [57] ABSTRACT Process for the preparation of said alicyclic compounds.

4 Claims, No Drawings 2,6,6-TRIMETHYL- l-ALKENOYL-CYCLOHEXE- NONES SUMMARY OF THE INVENTION The invention relates to the use as perfuming and/or flavouring ingredients of oxygenated alicyclic compounds of formula wherein the symbol R represents an alkyl radical containing from 1 to 6 carbon atoms or a hydrogen atom, the symbol X represents a univalent radical of formula containing a double bond in one of the positions indicated by the dotted lines and wherein the index n represents the integers zero or 1 and each of the symbols R, R and R represents a hydrogen atom or one of them represents an alkyl radical containing from 1 to 6 carbon atoms and each of the others is a hydrogen atom, or of formula wherein the symbols R", R and R have the same meaning as indicated above, and wherein:

A. the six membered ring possesses either a single or an isolated or two conjugated double bonds in the positions indicated by the dotted lines; the indexes m and p represent the integers zero or 1;

one of the symbols Z represents an oxygen atom and each of the others represents one or two hydrogen atoms; or

B; the six membered ring possesses a double bond at position 1;

m and p are identical and equal to zero; the symbol 2 at position 4 represents a hydroxyl group and a hydrogen atom and each of the others represents two hydrogen atoms. The invention also relates to new oxygenated alicyclic compounds of formula wherein the symbols R, X and Z, the indexes m and p, 5 and the cyclic dotted lines have the same meaning as indicated above for formula I, letter A.

The invention finally relates to a process for the preparation of a compound of formula I, which comprises A. treating a compound of formula I l CO :H"' C 'CH R [5 2- l I wherein the epoxy ring is bound to positions 2 and 3 or 3 and 4 of the ring and wherein the side chain contains a double bond at position 2' or 3 as indicated by the dotted lines, the index n represents the integers zero or 1. the symbols R represents an alkyl radical containing from 1 to 6 carbon atoms or a hydrogen atom, each of the symbols R R and R represents a hydrogen atom or one of them represents an alkyl radical containing from 1 to 6 carbon atoms and each of the others represents a hydrogen atom,

by means of an acidic isomerizing agent, to afford a compound of formula wherein one of the symbols Z represents an oxygen atom and the other two hydrogen atoms and wherein the symbols R, R R and R have the same meaning as indicated above; or

B. oxydizing a compound of formula tions indicated by the dotted lines and wherein one of the symbols Y represents:

a hydroxyl group or a halogen, and a hydrogen atom.

or two hydrogen atoms.

and the other represents 1 or 2 hydrogen atoms. and wherein the symbols R. R R and R". the position of the double bond of the side chain and the index n are defined as under letter A. to afford a compound of formula 5 wherein one of the symbols Z represents an oxygen atom and the other represents 1 or 2 hydrogen atoms. and wherein the symbols R. R R and R the position of the cyclic double bond and of the double bond of the side chain and the index n are defined as indicated above; or

C. oxydizing a compound of formula wherein the symbols R. R R andRfl the position of the double bond of the side chain and the index n are defined as under letter B. to'afford a compound of containing two conjugated cyclic double bonds at 60 position 1 and 3. wherein the symbol Z represents an oxygen atom and wherein the symbols R. R R and R. the position of the double bond of the side chain and the index n are defined as indicated above: or

D. reducing the keto compound obtained according 65 to the process under letter C to afford a compound of formula possessing a cyclic double bond at position I and a double bond at position 2' of the side chain. wherein the index n is equal to zero and wherein the symbols Z. R. R R and R have the same meaning as indicated for formula Ic; or a compound of formula in which the ring either is saturated or contains an isolated double bond or two conjugated double bonds in the positions indicated by the dotted lines and wherein the symbols Z. R. R R and R are defined as indicated above.

BACKGROUND OF THE INVENTION One of the main objects of the aromatization of foodstuffs for instance is to restore the original quality and nature of the flavour. aroma and taste of a given foodstuff material. Very often in fact the organoleptic properties of foodstuffs particularly diminish or are somehow modified in the course of the processes of freezing and storage. or during the modifications. such as cooking or baking. to which the foodstuffs are subjected in order to yield an edible material.

In the past the aromatization was mainly achieved by using materials of natural origin. Nowadays. however. synthetic chemical compounds are used at an ever increasing rate. Said compounds possess the advantage of being available very often in unlimited quantities and at prices lower than those of the natural materials.- Moreover. due to the fact that the flavouring character of a natural material is the result of the overall effect determined by the combination and interaction of each of its constituents. the effects achieved by said natural material are very often not as well reproducible as those obtained by the use of the pure synthetic compounds.

In the field of perfumery the man in the art has to solve a similar problem in attempting to reconstitute the olfactive notes of certain natural essential oils or extracts. The perfumers creativity however is continually boosted by the finding of new synthetic compounds. the organoleptic properties of which will enable him to introduce unprecedented olfactive characters or nuances into new phantasy perfume compositions.

As a consequence. the problem that the chemical industry has to solve is to satisfy the increasing demand of organoleptically interesting chemicals in order to better suit the specific needs of flavourists and perfumers.

Whereas 2,6,6-trimethyll but- 1 -en-3-oyl cyclohex-l-en-3-one, a diketo compound of formula is known as possessing the typical odor of ionones, reminiscent more particularly of that of violets [see Agr. Biol. Chem. 35, 962 1971)], we have surprisingly found that 2,6,6-trimethyll-( but-Z-enoyl )-cyclohexl en-3-one. a diketo compound of formula possesses an original sweet and fruity odor, reminiscent more precisely of that of pears or apples for example. This particular odour is moreover clearly different from that of the corresponding monoketo derivative, namely 2,6,6-trimethyll but-2-enoyl )-cyclohexl-ene. known in the art as B-damascone, this latter compound possessing a characteristic fruity, minty and slightly harsh odor [see Helv. Chim. Acta 54, 531 1970)].

Equally different from the odour of B-damascone is the odour of 2,6,6-trimethyl-l-(but-2-enoyl)-cyclohexl-en-4-ol, a compound of formula which develops an original and tenacious fruity and flowery odoriferous note.

Although the odour of the above mentioned compounds of the invention is reminiscent, in some instances, of that of known alicyclic ketones [see e.g. Belgian Pat. No. 750049]. their olfactory properties are definitely different when the compounds of the invention are used as perfuming ingredients in a perfume composition. This characteristic olfactory effect is well marked in a fruity or a floral perfume composition for example. Whereas B-damascone is particularly appreciated in the art for the reconstruction of the top-notes" in a synthetic rose oil for example. both 2,6.6-trimethyll but-Z-enoyl )-cyclohex- 1 -en-3-one and 2.6,6-trimethyl-1-( but-2-enoyl )-cyclohexl-en-4- ol typically enhance the background notes of the said oil. conferring to the thus reconstituted oil an unprecedented harmonious olfactive character.

PREFERRED EMBODIMENT OF THE INVENTION We have found that the oxygenated alicyclic compounds of formula I possess unique organoleptic properties and represent very useful ingredients for the preparation of perfumes or perfumed products as well 6 as for the reconstruction of essential oils. We have equally found that the said compounds are particularly useful in the preparation of various artificial flavors and for flavoring foodstuffs, animals feeds, beverages, pharmaceutical preparations and tobacco products.

In the field of perfumery for example, the compounds of formula I develop a pleasant and original sweet and slightly fruity odor, reminiscent in some instances of that of pears, apples, mandarines or even apricots. The said compounds can also improve, enhance or modify various olfactive notes, e.g. woody, flowery, herbal or even leatherlike notes. The use of the above compounds is therefore very useful in fine perfumery as well as for the manufacture of perfumed products as e.g. soaps, detergents, waxes, household materials or cosmetic preparations.

When the compounds of formula I are used as perfuming ingredients in perfume compositions unique effects are achieved by the use of proportions comprised between about 0.5 and about 5% of the total weight of the perfume composition. Depending upon the desired effect or upon the nature of the other constituents of a given composition, concentrations as low as 0.01% or as high as from about 10 to 20% (parts by weight), can be used. When the said compounds are used as reinforcing ingredients in perfumed bases, the

concentrations used can be as high as about of the total weight of the said base.

The compounds of formula I are also appreciated in the flavor industry. Depending upon the nature of the products in which they are incorporated, the said compounds develop a sweet and fruity. slightly flowery and woody gustative note, reminiscent in some instances'of that of honey. The compounds of formula I may also improve, enhance or modify various gustative notes such as herbal, winey, green, woody or waxy notes for examples, or any combination of the said notes.

Depending upon the nature of the flavored material or upon the desired effect, the proportions used can vary within wide limits, being of the order of 1 ppm to 1% of the total weight of the flavored material. Useful effects can be achieved by the use of proportions comprised between about 50 and about ppm of the total weight of the flavored product.

When the said compounds are used as ingredients for the preparation of artificial flavors. they can be used in proportions comprised between about 0.1 and about 15% of the total weight of the said flavoring composition, the proportions preferably used being of the order of l to 10%.

It is to be understood that the limits of the proportions given above do not represent absolute limits; in certain cases, where special organoleptic effects are desired, the compounds of the invention may be used in higher or lower concentrations than those mentioned above. The term foodstuff is used in this specification in its broadest sense. It also comprises products such as coffee. tea or chocolate.

Among the compounds of formula I which can be used according to the present invention. only two of them are known compounds, namely 2,6,6-trimethyl-l- (but-2-enoyl )-cyclohexl -en-4-ol and 2.6.6-trimethyll-butyryl-cyclohex-l-en-4-ol [see Agr. Biol. Chem. 36, 168 (1972)].

2.6,6-Trimethyll but-Z-enoyl )-cyclohex-.l -en-4-ol may be prepared from an alicyclic triol according to the method illustrated hereinafter. This method consists in converting an acetylenic triol into the desired keto-alcohol according tothe following reaction scheme:

The said acetylenic triol is converted into the desired hydroxy-ketone by means of an acidic dehydrating agent such as a strong mineral or organic acid. Sulfuric acid is the preferred one. The preparation of the above mentioned compounds is given hereinbelow:

2,6,6-Trimethyll but-2-enoyl )-cyclohex- 1 -en-4-ol: a mixture of 16 g of 2,6.6-trimethyl-1-(3-hydroxybutynyl)-cyclohexan-l,4-diol [prepared according to the method described in J. Chem. Soc. 1971, 404] and 160 ml of a 30% aqueous solution of H. ,SO was stirred at room temperature for hours. The reaction mixture was then extracted with ether and the organic layer was washed, dried and evaporated according to the usual techniques. The distillation (ca. lC/0.02 Torr) of the obtained residue finally gave 12 g of an oily material containing 75% of the desired compound. The pure compound, obtained by means of a preparative vapour phase chromatography, was identical with that described in Agr. Biol. Chem, op. cit.

MS: M" 208 m/e: 193 175 (41); 149

2.6.6'Trimethyll -butyryl-cyclohexl -en-4-ol: this compound was obtained by reducing the above corresponding unsaturated derivative, by means of LiAlH n 1.4949; df" 0.9986

MS:M =2lO(2);m/e: 177(3); 167 (100); 149(5);

Among the compounds of formula I which can be used according to the present invention, the following new compounds possess particularly valuable organoleptic properties:

2.6,6-trimethyll-butyryl-cyclohexan-3-one.

2,6,6-trimethyl-1-(but-Z-enoyl)-cyclohexan-3-one,

2,6.6-trimethyll but-2-enoyl )-cyclohexl-en- 3-one,

2,6.6-trimethyll-( but-Z-enoyl )-cylohexan-4-one,

2,6.6-trimethyll but-Z-enoyl )-cyclohex-2-en- 4-one, 2,6,6.-trimethyl-1-butyryl-cyclohexan-S-one, 2.6.6-trimethyl- 1 -butyryl-cyclohex- 1-en-5-one. 2,6.6-trimethyll-butyryl-cyclohex-Z-en-S-one. 2,6.6-trimethyll-butyry1-cyclohex-3-en-5-one, 2.6.6-trimethyll-butyryl-cyclohexal 3-dien-5-one. 2.6.6-trimethyl-1-(but-2-enoyl)-cyclohex-l-en- 5-one. and

2,6.6-trimethyll but-2-enoyl )-cyclohexal ,3-dien- 5-one.

According to a further subject matter of the present invention, epoxy compounds of formula II are converted into the corresponding diketo derivatives by means of a treatment with an acidic isomerizing agent.

Suitable isomerizing agents are mineral acids such as e.g. sulfuric or phosphoric acid, or Lewis acids such as BF or MgBr for example, these latter reagents being used in the presence of a solvent such as e.g. ethyl ether or benzene [see H. 0. House, Modern Synthetic Reactions, W. A. Benjamin Inc., New York. 1965, p.

122-3]. An acidic diatomaceous earth in the presence of an inert organic solvent may also be used. Suitable solvents are benzene, dioxane, tetrahydrofurane or ethyl acetate for example, or any mixture of at least two of the said solvents. The isomerization reaction is generally carried out at a temperature comprised between 50 C and the boiling point of the chosen solvent or mixture of solvents. However the given temperatures may vary within a broader range when particular reaction conditions are required.

According to a preferred embodiment of the process of the invention, the said isomerization is effected by heating the compound of formula II at a temperature near to C, in the presence of an acidic diatomaceous earth and dioxane. Thus, 2,6,6 trimethyll-( but- 2-enoyl)-cyclohexan-3-one is prepared from either 2,6,6-trimethyl-2,3-epoxy- 1 but-2-enoyl )cyclohexane or 2,6,6-trimethyl-2,3-epoxy-l-(but-3-enoyl)- cyclohexane.

The compounds of formula 11 used as startingmaterial in the above process may be obtained by epoxidizing the corresponding cyclohexenic derivatives according to the usual techniques.

As indicated above compounds of formula [11 are converted into keto derivatives lb by means of an oxidation. Said oxidation may be carried out by means of the reactants commonly used in order to convert a hydroxy group, a halogen or an activated methylene group into the corresponding carbonyl group. Suitable oxidation agents are oxygenated derivatives of a transition metal such as e.g. chromium, nickel or manganese. [see H. 0. House, op. cit., p. 718]. CrO or MnO or a chromate or a permanganate of an alkali metal, used in the presence of a mineral acid such as sulfuric acid for example are the preferred reagents.

CrO in the presence of an organic base such as pyridine may also be advantageously used as well as a compound such as ter-butyl chromate [see J. Org. Chem. 34, 3587 (1969) and Agr. Biol. Chem. 35, 962 (1971)].

Thus, according to a preferred embodiment of the process of the invention, 2,6,6-trimethyl-l-(but-2- enoyl)-cyclohex-l-en-3-one may be obtained from 3- bromo-2. 6,6-trimethyll-( but-Z-enoyl )-cyclohexl-ene, by means of an oxidation with CrO in the presence of sulfuric acid. In an analogous way, 2,6,6- trimethyl-l-(but-2-enoyl)-cyclohexan-4-ol and 2,6,6- trimethyl-l-(but-2-enoyl)-cyclohex-2-ene were con verted into 2,6.6-trimethyl-l-(but-2-enoyl)-cyclohexan-4-one and 2,6,6-trimethyll but-Z-enoyl cyclohex-2-en-4-one, respectively.

The compounds of formula 111 used as starting material in the above process may be obtained in accordance with known methods [see for example French Pat. No. 1,591,031].

Compounds of formula IV may also be converted into the desired keto compounds by means of an oxidation. The said oxidation may be carried out by means of the reagents mentioned above or by means of selenium 9 dioxide. this latter reagent being the preferred one [see H. 0. House. op. cit.. 2nd edition, p. 407-411]. 2,6,6-Trimethyl-1-(but-2-enoyl)-cyclohexa-1.3-

diene is thus easily converted into 2,6,6-trimethyl-l- (but-2-enoy1)-cyclohexa-1 .3-dien--one. The cyclohexadiene derivative of formula IV may be prepared in accordance with the method described in Heir. Chim. Acta 54. 1899 (1971).

Finally. compounds of formula Ic may be converted into compounds Id and/or [e by means of a reduction. The said reduction is effected by means of a catalytic hydrogenation in the presence of Raney nickel, platinum oxide or palladium on charcoal, for example. Raney nickel. used in the presence of an inert solvent such as e.g. ethyl alcohol, is the preferred hydrogenation catalyst.

According to a preferred embodiment of the process of the invention, the catalytic hydrogenation of 2,6,6- trimethyl- 1-( but-2-enoyl )-cyclohexal ,3-dien-5-one yields a mixture comprising 2,6,6-trimethyl-l-butyrylcyclohexan-S-one, 2.6,6-trimethyl- 1 -butyryl-cyclohex- 1 -en-5-one. 2,6.6-trimethyl- 1 -butyrylcyclohex-2-en- 5-one. 2.6.6-trimethy1-1-butyryl-cyclohex-3-en-5-one, 2.6.6-trimethyl-1-butyry1-cyc1ohexa-1,3-dien-5-one and 2,6,6-trimethyll but-Z-enoyl )-cyclohexl-en- 5-one.

Each of the above compounds may be obtained in a pure state by separating the thus obtained mixture by means of a preparative vapour phase chromatography.

The preparations and utilization of the compounds of this invention are illustrated in a more detailed way by the following specific examples wherein the temperatures are given in degrees Centigrade. The other compounds included within this invention can be prepared in the same or similar manner and possess similar organoleptic properties.

EXAMPLE 1 2,6,6-Trimethyll but-2-enoyl )-cyclohexan-3 -one 5.0 g (24 mMole) of 2,6,6-trimethyl-2,3-epoxy-1- (but-2-enoyl)-cyc1ohexane dissolved in 50 ml of dioxane were heated to reflux under a nitrogen atmosphere, in the presence of 1.0 g of acidic diatomaceous earth. After 2 hours of heating, the vapour phase chromatography analysis showed a total disappearance of the starting material. The reaction mixture was then cooled and filtered on CELITE. After elimination of the volatile fractions and distillation of the obtained residue there were thus isolated 4.6 g of a semicristalline product, b.p. 6090/0.1 Torr.

Pure 2, 6,6-trimethyl- 1-( but-Z-enoyl )-cyclohexan- 3-one was finally obtained after cristallization of the crude material in petroleum ether (b.p. 40-60): 3.0 g (-60 70). mp. 76-77.

IR (KBr): 1710. 1675, 965 cm NMR (CCI 0.76 (3H, d, J=4 cps); 1.04 (3H, s); 1.14 (3H. s); 1.94 (31-1. d. J=7 cps); 6.0-7.15 (21-1. m) 8 ppm MS: 1 =208 (8); m/e 152 (1); 139 (18); 124 (1); 111 (23); 97 83 (4); 69 (100); 55-(22).

When 2.6.6-trimethyl-2.3-epoxy-1-(but-3-enoyl)- cyclohexane was used as starting material in the above process. the desired ketone was obtained with an analogous yield.

The 2.6.6-trimethy1-2.3-epoxy-1-( but-Z-enoyl cyclohexane used as starting material in the above process. may be prepared according to the following 10 procedure: to a cold mixture (0) of 14.2 g (74 mMole) of 2.6,6-trimethyl-1-(but-2-enoyl)-cyclohex-l-ene [prepared according to the method given in Helv. C/zim. Acta 53, 541 (1970)] and 7.0 g mMole) of anhydrous sodium acetate in 150 ml of CH Cl there were added a mixture of 13.3 g (ca. 60mMole of peracetic acid (40% in CH COOH) and 0.3 g of sodium acetate. The reactants were added dropwise, under vigorous stirring, in order to maintain the temperature of the reaction mixture between 0 and 10. After the said addition the reaction mixture was stirred overnight at room temperature, then diluted with 200 ml of water. After having been successively washed with water, 2N NaHCO and water, the organic layer was dried over MgSO, and evaporated to dryness to afford 14.2 g of a practically pure epoxide b.p. 78/0.01 Torr, 11 1.4901.

IR (neat): 1670, 1620. 965 cm NMR(CC1,): 0.89 (6H, 2s); 1.23 (31-1. 3); 1.85 (31-1, d, J=6 cps); 2.85 (1H. m); 6.27.0 (21-1, m) 5 ppm MS:M =208(l);m/e=193 (2); 175(1); 152(2); 137 (13); 123 (10); 107 (37); 97 (7); 81 (7); 69 (100); 55 (11). 2,6,6-Trimethyl-2.3-epoxy- 1-( but.-2-enoy1 cyclohexane was obtained according to the same procedure from the corresponding cyclohexene derivative [see Heir. Chim. Acta 53. 541 (1970)]. b.p. 7880/0.()1 Torr.

IR (neat: 3050. 1820, 1715, 1635, 990, 910 cm NMR (CCl 0.86 (3H. (1); 0.96 (31-1,.9); 1.36 (3H. s);

3.22 (1H. broad s); 4.86-6.2(31-1. m) 5 ppm MS: M 208 (0.1); m/e 167 (17); 149(4); 140 (11); 123 (42); 111 (33); (25); 84 (50); 69 (78); 55 (50); 43

EXAMPLE 2 2,6,6-Trimethyl-1-(but-2-enoyl)-cyclohexan-4-one A mixture of 11.0 g (37 mMole) of Na Cr- O .2H O. 5 ml of acetic acid, 3.5 g of concentrated H SO, and 41 ml of water was added at room temperature and under vigorous stirring to a solution of 7.0 g (33 mMole) of 2,6,6-trimethyll but-2-enoy1)-cyclohexan-4-o1 in 20 ml of benzene. The mixture was further stirred for one hour and finally diluted with water. The organic layer was then submitted to the usual treatments of washing and drying, and evaporated to dryness to afford 6.0 g (87%) of a crude keto compound. An analytical sample was purified byc'rystallization in hexane. m.p. 8385.

IR (KBr): 1710, 1680. 1650,1620. 962 cm NMR(CC1,): 0.92 (3H, s); 0.98 (3H. s); 0.93 (31-1. d, J=6 cps); 1.93 (3H, d, J=7 cps); 6.0-7.1 (2H. m) 5 MS: M =208 (8);m/e: 193 10); 166 (3); 151 (14); 137(4); (26); 111 (8); 95 (3); 83 (23); 69 (100); 55 (18).

EXAMPLE 3 2.6.6-Trimethyl-1-(but-2-enoy1)-cyclohex-1-en-3-one 1 1 After having been cooled at the reaction mixture was then filtered and concentrated under reduced pressure to afford 125 g of crude bromo derivative. This latter compound was used without any further purification for the subsequent reaction step.

b. 125 g of crude 3bromo-2,6,6-trimethyl-1-(but2- enoyl)-cyclohex-l-ene [prepared under letter a] were added dropwise to a mixture of 100 g (l Mole) CrO 100 ml acetic acid and 100 ml of water. kept at 2025. After addition of the reactants the reaction mixture was heated under stirring at 40 for 30 min., and finally diluted with l l of water. After neutralization of the reaction mixture by means of a aqueous solution of NaOH. the obtained mixture was submitted to a steam distillation 3 l of the thus obtained distillate were then extracted with ether (3 X 500 ml), the organic layer was washed with water, dryed over Na SO and finally concentrated under reduced pressure. There were thus obtained 68.2 g (73%) of a semicrystalline product, b.p. 71116/0.01 Torr, which was finally crystallized in hexane to afford 51.3 g (55%) of pure 2,6,6-trimethy1-1-(but-2- enoyl)-cyclohex-1 en-3-one, m.p. 6869 IR (CCl 1680, 1660, 1235, 970 cm NMR(CC1,): 1.18 (6H, s); 1.54 (3H, s); 2.0 (3H, d of d, J=6, J'=1,5 cps); 2.0 (2H, q, J=6 cps); 2,34 (2H. q. J=6 cps); 6.0-7.0 (21-I, m) 8 ppm MS: M 206;m/e=191.163,150, 138, 121,109,

The 2,6,6-trimethyl-1-( but-2-enoy1)-cyclohexl-ene used as starting material in the above process may be prepared in accordance with the method described in French Pat. No. l 591 031.

EXAMPLE 4 2,6,6-Trimethy1-1-(but'2-enoyl)-cyclohex-2-en-4-one 10 ml of acetic anhydride were first added to a solution kept at 10 of 3.5 g of Na Cr O .2H O in 10 ml of acetic acid and the obtained mixture was stirred for 1 hour. A solution of 2.1 g of 2,6,6-trimethyl-l-(but-2- enoyl)-cyclohex-2-ene [prepared according to the method described in Helv. Chim. Acta 53, 541 1970)], in 10 ml of acetic anhydride was then added to the above mixture. After having been stirred overnight at room temperature, the reaction mixture was then poured onto crushed ice and extracted with ether. After the usual treatments of washing, drying and evaporation, there was obtained 2.0 g of crude material containing 80% of the desired keto compound.

An analytical sample was obtained by purification by vapour phase chromatography. rn.p. 4344.

IR (neat): 1685, 1670, 1625, 970, 825 cm NMR(CC1,): 0.96 and 1.06 (6H, 28); 1.94 (3H, dof

d. J=7. J=2 cps); 2.54 (2H, d, J=16 cps); 3.32 (1H, s); 5.84 (1H. m); 6.22 and 6.95 (2H, d of m and d of d. J=16, J'=14, J"=6 cps) 8 ppm MS: 206 (1); m/e: 191 (0.1); 178 (0.1); 154

EXAMPLE 5 I 2,6.6-Trimethyl-l-(but-Z-enoyl)-cyclohexa-1,3 dien- 5-one 2.5 g 13 mMole) of 2.6.6-trlmethyll-(but-2-ehoy1)- c vc1ohexa-l.3-diene [prepared according to the method given in Helix C/zz'm. Aclu 54, 1899 (1971)] 12 dissolved in 50 ml of dioxane were heated, under nitrogen atmosphere, during 45 min. at 60, in the presence of 1.8 g 16 mMole) of selenium oxide. The reaction mixture was then cooled, concentrated under reduced pressure, and the obtained residue, diluted with 50 ml of acetic acid. was finally stirred at room temperature for 2 hours in the presence of 6 g of Raney nickel. The reaction mixture was then filtered, evaporated to dryness and the obtained residue was distilled (b.p. l00110/0.2 Torr) to afford 2.4 g of a material containing of the desired keto compound.

A pure sample was obtained by crystallization in hexane, m.p. 6667.

IR (neat): 1665, 1640, 970 cm NMR(CC1,): 1.18 (6H, 2s); 1.81 (3H, s); 1.95 (3H. d, J=7 cps); 5.9 (1H, d, J=10 cps); 6.2 (1H, m); 6.72 (1H, d, J=l0 cps); 6.4-6.9 (1H, m) 8 ppm MS: M 204 (3); m/e= 136 (22); 107 (4); 91 (8); 69(100);41(15). I

EXAMPLE 6 Catalytic hydrogenation of 2,6,6-trimethy1- l-( but-2-enoyl )-cyc1ohexa- 1 .3-dien- 5-one tography and the following compounds were identified:

a. 2,6,6-trimethyl-1-butylryl-cyc1ohex-2-en5-one IR (neat): 1700, 825 cm NMR (CC1 0.90 (3H, 1, J=7 cps); 0.94 and 1.1 (6H, 2s); 1.8 (3H, broad s); 2.82 (2H, m); 3.08 (1H, s); 5.6 (1H, m) 6 ppm MS: M =208 (0.1);'m/e= 137 (42); 119 (64); 109 (19); (12); 82 (24); 71 (87); 55 (12); 43 27 (16). b. 2,6,6-trimethyl-l-butyryLcyclohex-1-en-5-one n 1.4837; (1 0.9988 IR (neat): 1715, 1695 cm NMR(CC1,): 0.94 (3H, 1, J=5 cps); 1.16 (6H, 2s);

1.68 (3H, s); 2.45 (4H, m) 8 ppm MS: M =208 (10); m/e: (66); 137 (100); 123 (82); 109 (17); 95 (42); 81 (12); 71 (35) 55 (23): 43 (67); 27 (23). c. 2,6,6-trimethyl-l-butyryl-cyclohexa-1,3-dien-5one IR (neat): 1670, 1640, 1575 cm NMR (CCl 0.95 (3H, t. J=6 cps); 1.21 (6H. 2s);1.85 (3H. s); 5.91 (1H, d. J=l0 cps); 6.72 (1H. d, J=l0 cps) 8 ppm MS: M",=206 (0.1); m/e= 136 100); 121 (10); 109

(18); 91 (19); 79 (6); 71 (26); 43 (41). d. 2,6,6-trimethy1-1-butyryl-cyclohexan-5one 11 1.4732; d 0.9874 IR (neat): 1710 cm NMR (CC1 0.95 (3H. 1, J=6 cps); 0.87 and 1.2

(6H, 23); 2.78 (1H, m) 8 ppm MS: M 210 (20); m/e'= 167 (20); 139 45); 127 i e 2,6,6-trimethy1- 1-(but-2-enoyl)-cyc1ohex-1en- 13 IR (neat): 1710. 1670. 1640. 1610. 965cm 'NMR(CCl 1.09 (6H. 2s): 1.62 (3H. s); 119 (3H.d'.

J=6 cps); 2.48 (4H, m); 6.05 6 ppm MS: M" 206 (12); m/e =19] 178(8); 164 (65); 149 (63); 137 (33); 121 (60); 109 8-1 (10); 79 (14); 69 (100); 55 41 (73). f. 2.6.6-trimethyl-1-butyryl-cyclohex-3-en-5-one IR (neat): 1710. 1680 cm NMR (CCl 0.88 (3H. t, J=7 cps); 0.98and 1.12 (6H. 23); 1.1 (3H. d, J=6 cps); 5.75 (1H, d, J=ll cps); 6.26 (1H, d, J=11 cps) 8 ppm MS: M 208 (7); m/e 137 (12); 123 (19); 109

(13); 82 (100); 69 (19); 59 (9); 43 (34). g. 2,6,6-trimethyl- 1 -butyryl-cyclohex- 1 -en-5-ol IR (neat): 3450, 1690 cm f NMR (CCl 0.96 (31-1, 1, J=7 cps); 1.03 and 1.06 (6H, 2s); 1.54 (3H, s); 3.4 (1H, t, J=5 cps) 5 ppm MS: M 210 (5); m/e 167 (100); 149 (28); 139 121 (61); 105 (13); 93 (34); 79 (18); 71 (34); 55 (25); 43 (77).

EXAMPLE 7 A base perfume composition for a deodorizing perfume was prepared by admixing the following ingredients (parts by weight):

in dielhyl phthalate By adding 10 g of 2,6,6-trimethyl-1-(but-2-enoyl)- cyclohexan-3-one to 90 g of the above base composition, there was obtained a new perfume composition possessing a very harmonious and natural character. Moreover, the fruity note of the above perfume was particularly well enhanced and tenacious.

By replacing the above keto compound by 2,6,6- tn'methyll but-Z-enoyl )-cyclohexl -en-3-one or by one of the alicyclic ketones described in the course of the present specification. analogous effects were observed. In some cases the olfactive effect was less pronounced.

EXAMPLE 8 A base perfume composition for a fine perfume was prepared by admixing the following ingredients (parts by weight):

Absolute jasmine l0 Patchouli l0 Pimento oil (leaves) 20 Hydroxycitronellol 50 1H, m); 6.6 1H.m-)

-cont1nued Synthetic rose 100 alsomethyl ionone 100 Synthetic jasmine I50 Vetiveryl acetate Dodecanal 10 71* ll) Undecenal l0 80 Dec-anal 10 71* 20 Nonanal 10 22* 5 Oriental sandalwood oil 25 Methyl 2-pentyl-3-oxo-cyclopentylacetate 10 Synthetic bergamot 55 Ylang extra 20 Natural degreased Civet 10 71* 20 Artemisia oil 10 Neroli bigarade 5 Synthetic violet 10 71* 10 Cyclopentadecanolide 10 92* Coumarin l0 Heliotropin 20 Total 920 *in diethyl phthalate By adding to 92 g of the above base composition 8 g of 2,6.6-trimethyl- 1 but-2-enoyl )-cyclohexan-3-one there was obtained a new perfume composition possessing a very harmonious and natural character. Moreover, the fruity note of the above perfume was particularly well enhanced and tenacious.

By replacing the above keto compound by 2,6,6- trimethyl-l-(but-2-enoyl)-cyclohex-1-en-3-one a simi lar effect was observed.

EXAMPLE 9 A base perfume composition for a flowery-type perfume was obtained by admixing the following ingredients (parts by weight):

a-lonone 50 Civettone 10 71* v 30 Synthetic jasmine 200 Synthetic rose 100 Levorotatory 4-methyl2-( Z-methylprop-2-enyl)-tetrahydropyrane 10 '7r* l0 Heliotropin 50 Undecenal 1071* 15 Decanal l0 l0 Octanal 10 71* 5 a-Phenylethyl acetate 15 Benzyl propionate 20 Petitgrain bigarade 50 Nerol 20 Phenylethyl propionate 20 p-Hydroxyphenylbutan-Il-one l 71* 10 Linalol 70 Linalyl acetate 50 Ylang 20 Geranyl acetate 70 Citronellyl acetate 60 cis-Hex-Z-enyl acetate 5 Diethyl phthalate Total 1000 *in diethyl phthalate By adding 10 g of 2,6,6-trimethyl-l-(but-2-enoyl)- cyclohex-1-en-4-ol to 90 g of the above composition. there was obtained a new perfume composition possessing a very harmonious odor. The fruity-flowery note of the said perfume was moreover particularly well rounded.

EXAMPLE 10 A base flavouring composition of the Tutti-Frutti type was prepared by admixing the following ingredients (parts by weight):

Vanillin 25 Ally] caproate l0 Citral 15 Amy] butyrate 35 Sweet orange oil 50 -continued Ethyl hutyrate 75 Ethyl acetate lSU Amyl acetate I51) Lemon oil 250 Orange terpenes 240 Total 1000 Two flavoring compositions were then prepared as indicated below (parts by weight):

Both mixtures A and B were then used for the preparation of the following foodstuffs. in the proportions of 100 g of flavouring composition per 100 kg of foodstuff.

Ice-cream: An ice-cream mixture was prepared from 1 l of milk. 5 egg yolks and 250 g of sugar in the following manner: the milk was heated, the sugar and the egg yolks were mixed and the hot milk was added to the mixture while stirring. Stirring was continued until the mass thickened, and the flavor was added. The mixture was then frozen in the usual manner.

Pudding: A mixture of 60 g of sugar and 3 g of pectine was added to 500 ml of hot milk, while stirring. The mixture was brought to the boil for a fewseconds, the flavor was added and the mixture allowed to cool.

The foodstuffs prepared as described above were then tasted by a panel of flavour experts who declared that the test foodstuffs possessed a more pronounced, well rounded, fruity and slightly flowery taste as compared with the control" foodstuffs, reminiscent of that of melon.

By replacing, in the same proportions. the above ketone by 2,6,6-trimethyll-( but-Z-enoyl )-cyclohexan- 3-one, an analogous effect was observed.

EXAMPLE 1 l 7 g of a 1% ethanolic solution of 2,6,6-trimethyl-l- (butQ-enoylJ-cyclohex-l-en-3-one were sprayed onto 100 g of an American blend tobacco mixture. The tobacco thus flavored was used for the manufacture of test cigarettes, the smoke of which was then subjected 16 to organoleptic evaluation by comparison with unflavoured control cigarettes. The tobacco used to prepare the control cigarettes was preliminarily treated with a corresponding amount of ethyl alcohol.

A panel of flavour experts defined the taste of the smoke of the test cigarettes as being more rounded than that of the control cigarettes, the said smoke possessing moreover a more marked fruity and flowery character.

We claim:

I. Oxygenated alicyclic compounds of the formula wherein the symbols R, R R" and R represent alkyl radicals containing from 1 to 6 carbon atoms or hydrogen atoms, provided that the total number of hydrogen atoms represented by the symbols R'-, R and R equals at least two; and containing a first double bond in one of the dotted line positions of the keto side chain and a second double bond in one of the endocyclic or the number two exocyclic dotted line positions of the ring; the indexes m and p represent the integers zero or one when the hydrogen atoms for which they are multipliers are connected to a double bonded or single bonded cyclic carbon respectively; one of the symbols Z represents-an oxygen atom when connected to an otherwise single bonded carbon and the other Z symbols represent one or two hydrogen atoms when connected to a double bonded or single bonded carbon respectively; and the index n represents the integers zero or one when the hydrogen for which it is a multiplier is connected to a double bonded or single bonded carbon atom, respectively.

2. 2,6,6-Trimethyll-( but-2-enoyl )-cyclohex- 1 -en- 3-one. 3. 4-one. 4. 5-one.

2.6,6-Trimethyll-( but-Z-enoyl )-cyclohex-2--.en-

2, 6,6-Trimethyll-( but-Z-enoyl )-cyclohexl-en 

1. OXYGENATED ALICYCLIC COMPOUNDS OF THE FORMULA
 2. 2,6,6-Trimethyl-1-(but-2-enoyl)-cyclohex-1-en-3-one.
 3. 2,6,6-Trimethyl-1-(but-2-enoyl)-cyclohex-2-en-4-one.
 4. 2,6,6-Trimethyl-1-(but-2-enoyl)-cyclohex-1-en-5-one. 